(Newser)
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Tomorrow, Wisconsinites will decide whether to keep Gov. Scott Walker or boot him in favor of Milwaukee Mayor Tom Barrett, in what Chris Cillizza of the Washington Post is calling "the second most important and influential race of 2012 aside from the presidential," with "absolutely massive" stakes. Here's what you need to know as the clock ticks down:

Two polls released yesterday show the race virtually tied—Walker leads in each, but by thin margins. He's up 50-47 in one, 53-47 in the other, but both are within the margin of error, Reuters reports.

It's all about turnout now: "If Democrats turn out in the numbers they did in 2008, Tom Barrett will win a surprise victory. If they don't, Walker will survive," the head of Public Policy Polling says. The agency managing the election is predicting turnout somewhere between 60% and 65%—above 2010's 49.7%, but below 2008's 69.2%

"If there's any state that epitomizes what the permanent campaign feels like, it's this one," observes David Catanese of Politico. This will be the seventh time Wisconsin has gone to the polls in the last 14 months, thanks to various recalls.

All those campaigns are expensive: Through May 21, $110 million had been spent on political ads.

President Obama will be closely watching the results, because he's counting on Wisconsin in November, the New York Times points out. "A Republican victory here could set off a wave of adjustments in the lineup of swing states."

If Scott Walker wins, Cillizza expects to hear presidential rumblings surrounding him. A lot is on the line for Barrett, too; this would be his third gubernatorial defeat, likely ending his statewide ambitions.

Organized labor has a lot to lose, too. A Walker win would be both an affirmation of his anti-union policies, and a signal that unions have lost their political juice; they opposed Barrett in the primary, and lost there, too.